Process for manufacturing combustion chamber and/or nozzle of a rocket

ABSTRACT

Process for manufacture of a combustion chamber and/or nozzle of a rocket engine wherein a plurality of straight pipes are first longitudinally disposed and bonded together to form a cylindrical chamber and then the chamber is shaped to form a nozzle configuration, the pipes possibly additionally including cooling pipes and inserts disposed therein.

United States Patent Simon 1 1 Feb. 29, 1972 [54] PROCESS FORMANUFACTURING [56] References Cited COMBUSTION CHAMBER AND/OR UNITEDSTATES PATENTS NOZZLE OF A ROCKET 2,976,679 3/1961 Dalgleish ..29/157 CUX [72] inventor: Michael Simon, Hamburg-Othmarschen, 3 35 4/19 3Tumavicus go 17 C UX rm y 3,177,935 4/1965 Rosman ..60/267 X [73]Assignee: Maschinenfabrik Augsburg-Numberg A 3,349,464 1967 Becker et a1..29/157 "engesenschafl Primary ExaminerJohn F. Campbell [22] Filed:Mar. 17, 1969 Assistant Examiner-D. C. Reiley AttorneyCraig, Antonelli,Stewart & Hill [21] App1.No.: 807,703

[57] ABSTRACT Foreign Application Priority Data Process for manufactureof a combustion chamber and/or nozzle of a rocket engine wherein aplurality of straight pipes Mar. 15, 1968 Austria ..A 2619/68 are firstlongitudinally disposed and bonded together to form a cylindricalchamber and then the chamber is shaped to form a [52] US. Cl ..29/157,/267, 239/265.11 nozzle configuration the pipes possiby additionallyincluding [51] Illt. i cooling p p and inserts disposed therein. [58]Field of Search ..60/267; 29/157 C; 239/265.11

3 Claims, 6 Drawing Figures Patented Feb. 29, 1972 3,644,974

INVENTOR MICHAEL SIMON BY .7 H 2; ATTORNEYS PROCESS FOR MANUFACTURINGCOMBUSTION CHAMBER AND/OR NOZZLE OF A ROCKET The invention comprises acombustion chamber and/or nozzle of a rocket engine and process formanufacture thereof, the inner and outer walls of the combustion chamberand/or nozzle being formed by individual small pipes which run in alongitudinal direction and are joined together, and in which the fuelsto be fed into the combustion chamber for combustion are preheated orprevaporized.

The process as used up to now for manufacturing such a propulsion systemwhich basically consists of a combustion chamber and a nozzle of arocket engine, required that first each individual small pipe had to beshaped according to the desired combustion chamber and nozzle contourand that, only subsequently, all shaped pipes were brazed or weldedtogether to form the walls of the combustion chamber and nozzle.

The described preshaping of each individual small pipe is a timeconsuming and costly process. Therefore, the present invention isdirected to the solution of the problem by developing a process formanufacturing the combustion chamber and/or nozzle of a rocket engine,which is superior to all other previously known processes, in that itreduces manhours and thus manufacturing costs.

In order to solve the problem, the invention proposes that, in a processof the above-mentioned type, a cylindrical chamber would be producedfirst by brazing or welding the pipes together and only subsequentlywould the shaping of this chamber according to the desired combustionchamber/nozzle geometry be carried out. Moreover, for regenerativecooled rocket combustion chambers and subcritical cooling agent pressurevalues, there is a known requirement that the cooling agent must beprevaporized prior to its entry into the cooling duct itself. Onedifficulty with relatively short expansion nozzles, whereprevaporization at the nozzle outlet is not possible without danger, isto prevaporize the initially liquid cooling agent in a type of feed andreturn cooling duct by means of the vaporized gaseous cooling agentwhich subsequently flows back through the cooling duct.

The invention proposes that, with a combustion chamber and/or nozzlewhich feature feed and return cooling ducts for preheating orprevaporization of the liquid cooling agent, additional small pipes,e.g., for the cooling agent feed duct are arranged inside thoseindividual small pipes of the cylindrical chamber, which are, e.g.,intended to form the cooling agent return duct, this process takingplace prior to their shaping to the desired combustion chamber/nozzlegeometry, the outer and inner pipes being joined in such a manner that,upon completion of the shaping process, the areas required for brazingor welding will preferably lie on the outer walls of the combustionchamber and/or nozzle.

Furthermore, the invention proposes that, with a combustion chamberand/or nozzle, the feed and return cooling ducts of which featurefillers which provide for the flow sections and cooling agent velocitiesrequired to ensure adequate cooling efficiency, all small pipes which,at first, form a cylindrical chamber and are intended to serve as feedand/or return ducts for the cooling agent, are provided with suitablefillers prior to their shaping to the desired combustion chamber and/ornozzle geometry.

It is an object of the present invention to provide a process formanufacture of the combustion chamber and/or nozzle of a rocket enginewhich substantially eliminates the disadvantages inherent in prior knownprocesses.

It is another object of the present invention to provide a process ofthe type described in which a substantial reduction in manufacturingtime and cost is achieved.

It is a further object of the present invention to provide a process ofthe type described wherein shaping of the combustion chamber and/ornozzle is effected only after assembly of the components thereof.

It is still another object of the present invention to provide a novelcombustion chamber and/or nozzle construction as made by theabove-mentioned process.

These and other objects features and advantages will become apparentfrom the following detailed description thereof when taken inconjunction with the accompanying drawings which illustrate the featuresof the present invention, and wherein:

FIG. 1 is a longitudinal sectional view of a chamber representing afirst stage of manufacture;

FIG. 2 is a section taken along line II--ll of FIG. 1;

FIG. 3 is a longitudinal sectional view of the chamber of FIG. 1 afterhaving been shaped in accordance with the present invention, and

FIG. 4, 5 and 6 are partial cross-sectional views through the chamberillustrating various structural embodiments of the invention.

Turning now to the more specific features of the invention inconjunction with the drawings, FIGS. 1 and 2 illustrate a chamber 1,initially of cylindrical shape, consisting of individual, narrowlyspaced small pipes 3, coaxially arranged with regard to the longitudinalcenterline 2 of the chamber. The straight pipes 3 are welded or brazedtogether initially, for example at contact areas 4, to form thesubstantially cylindrical chamber.

In the next stage of the process the chamber 1, formed by individualpipes 3, is shaped according to the desired combustion chamber nozzlegeometry (FIG. 3) by means of an apparatus, not illustrated on thedrawings. The combustion chamber section is designated 5 and the nozzlesection 6. Thus, the need to individually shape the small pipes formingthe chamber prior to assembly which resulted in the great expenditure oftime and cost is eliminated in a relatively simple manner.

FIG. 4 shows, as a structural embodiment, a partial cross section of acombustion chamber/nozzle casing. The only variation of this embodimentas compared to the one shown in FIG. 2, is the arrangement of additionalsmall pipes 8 inside pipes 7. Pipes 7, for example, may be used ascooling agent feed ducts, which the inner pipes 8 may be used as coolingagent return ducts. In addition, FIG. 4 shows that pipes 7 and 8 arebrazed or welded together at areas 9, i.e., at the outer wall of thecombustion chamber/noule casing inner and outer walls formed by pipes 7.By fixing pipes 8 at areas 9, i.e., at points along the outer peripheryof the chamber, it is accomplished that the brazed or welded jointsrequired for fixing pipes 8 are not immediately subjected to the hightemperatures which are primarily encountered during operation at theinner walls of the combustion chamber/nozzle casing. Pipes 7 arenarrowly spaced and brazed or welded together at areas 10.

FIG. 5 shows a further partial cross section of a combustionchamber/nozzle casing which differs from the embodiment illustrated byFIG. 4 in that fillers 13 are arranged in spaces 12, formed by outerpipes 10 and inner pipes 11, in order to reduce the flow areas of spaces12, formed by pipes 10 and 11, at certain areas of the combustionchamber or nozzle. Brazed or welded areas for fixing fillers 13 inspaces 12 onto the walls of outer and inner pipes 10 and 11 aredesignated 13' and 13", respectively.

In a further structural embodiment illustrated in FIG. 6 outer pipes 14and inner pipes 15 are provided with elliptic sections as illustrated bythe partial cross section of the combustion chamber/nozzle casing.Fillers 16 are arranged between pipes 14 and 15 in such a manner thatonly cross sections 17 remain open for the fuel flow through pipes 14.Pipes 14 are brazed or welded together at areas 18 to form an integralcombustion chamber/nozzle unit. The brazed or welded joints for securingfillers 16 to the walls of outer pipes 14 in spaces 17 and also to thewalls of inner pipes 15 are designated 16' and 16", respectively.

It should be noted that fillers l3 and 16, shown in FIGS. 5 and 6, neednot necessarily extend over the total length of the inside of associatedpipes 10 and 14, but may be arranged only at predetermined areas insidepipes 10 and 14, in such a manner as to ensure adequate cooling of thosezones of the combustion chamber/nozzle walls especially subjected tohigh temperatures.

While I have shown and described several embodiments in bonding saidmain pipes having said feed pipes secured accordance with the presentinvention, it is understood that therewithin together along their sidesto form a cylindrithe same is not limited thereto but is susceptible ofnumerous cal chamber, and then, changes and modifications as known to aperson skilled in the shaping said cylindrical chamber to provide adesired nozzle art, and we therefore do not wish to be limited to thedetails 5 C gurati n. shown and described herein but intend to cover allsuch f as q f claim 1, further Including P to changes and modificationsas are within the scope of a person the bondmg 0f 831d mam PP together,killed in the an interposing between said feed pipes and the main pipesinto Iclaim: which they are inserted filler members by which the feed 1.Process for manufacturing a combustion chamber and/or P p are secured581d P p noule of a rocket engine, the inner and outer walls of which ff defined claim Whemm 531d p of bondare formed of longitudinallyextending main pipes including mg mam P p loge'lhermcludes therein feedand return cooling passages for preheating or ahgmflg S'ald f P'PF so fthe secu'l'mg P f the prevaporizingaliquid cooling agent, the stepscomprising: mall} P p wlt h associated feed P p l5 P insertinginto eachmain pipe asmaner diameter feed pipe; outside of a circle formed by thecenters of said main securing said feed pipes to the associated mainpipes at a point of the inner circumference thereof,

1. Process for manufacturing a combustion chamber and/or nozzle of arocket engine, the inner and outer walls of which are formed oflongitudinally extending main pipes including therein feed and returncooling passages for preheating or prevaporizing a liquid cooling agent,the steps comprising: inserting into each main pipe a smaller diameterfeed pipe; securing said feed pipes to the associated main pipes at apoint of the inner circumference thereof, bonding said main pipes havingsaid feed pipes secured therewithin together along their sides to form acylindrical chamber, and then, shaping said cylindrical chamber toprovide a desired nozzle configuration.
 2. Process as defined in claim1, further including prior to the bonding of said main pipes together,interposing between said feed pipes and the main pipes into which theyare inserted filler members by which the feed pipes are secured to saidmain pipes.
 3. Process as defined in claim 1, wherein said step ofbonding said main pipes together includes aligning said main pipes sothat the securing point of the main pipes with their associated feedpipes is positioned outside of a circle formed by the centers of saidmain pipes.